Stephen reported that on KASAN builds he's seeing:
vmlinux.o: warning: objtool: user_exc_vmm_communication+0x15a: call to __kasan_check_read() leaves .noinstr.text section
vmlinux.o: warning: objtool: exc_debug_user+0x182: call to __kasan_check_read() leaves .noinstr.text section
vmlinux.o: warning: objtool: exc_int3+0x123: call to __kasan_check_read() leaves .noinstr.text section
vmlinux.o: warning: objtool: noist_exc_machine_check+0x17a: call to __kasan_check_read() leaves .noinstr.text section
vmlinux.o: warning: objtool: fred_exc_machine_check+0x17e: call to __kasan_check_read() leaves .noinstr.text section
This turns out to be atomic ops from unwind_reset_info() that have
explicit instrumentation. Place unwind_reset_info() in the preceding
instrumentation_begin() section.
Fixes: c6439bfaab ("Merge tag 'trace-deferred-unwind-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251105100014.GY4068168@noisy.programming.kicks-ass.net
cf76553aaa